Instrument



' fnzzeniar 14m 22 F. H. HOPKINS INSTRUMENT 'Original Filed July 13, 19.40

Lijljllll? May 26, 1942.

Patented May 26, 1942 FFICE INSTRUMENT Frank H. Hopkins, Fairfield, Conn, assignor to Manning, Maxwell & Moore, Incorporated, New York, N. Y., a corporation of New Jersey Original application July 13,1940, Serial No. 345,321. Divided and this application April 26, 1941,, Serial No. 390,461

'2 Claims. (01. 240-21) This invention pertains to instruments, for example pressure gauges, dial thermometers or the like, the present application being a division of f the copending application for Letters Patent Serial No. 345,321, filed by Frank H. Hopkins, July 30, 1940the instrument herein chosen for illustration, but without limiting intent, being a pressure gauge of the kind in which a plurality of graduated dials, each with its own individual index or pointer, are so relatively disposed as to be visible from different directionsfor instance the case may be provided with a dial at opposite sides (back and front), with the actuating mechanism for both pointers disposed in the space between the dials. a

It has previouslybeen proposed to illuminate the dial of such an instrument by means of a lamp or lamps enclosed within the instrument case, for example in a housing provided with an ofiset chamber at the topor side of the case proper and opening into the case so that the light from the lamp may pass around the edge of the dial and then by reflection from proper surfaces, impinge upon and illuminate the front face of the dial.

The present invention has for its principal object the improvement of instruments of the general class above referred to and in particular to provide such an instrument, whether having a single dial or a plurality of dials, with illuminating means operative to illuminate'each dial substantially uniformly and with a soft diifused light.

Other and further objects and advantages of the invention will be pointed out hereinafter in the following more detailed description and by reference to the accompanying drawing in which Fig. 1 is a front elevation, with certain parts broken away and with certain parts in vertical section, illustrating a multi-dial instrument, for instance a pressure gauge, of the direct reading type, provided with means for illuminating the dials;

Fig. 2 is a vertical section in the vertical plane of the index staffs of the instrument but showing the lamp housing in end elevation; and

Fig. 3 is a fragmentary vertical section substantially on the line 3-3 of Fig. 2.

Referring to Figs. 1,2 and 3 of the drawing which illustrates one desirable embodiment of the invention, the numeral I designates the case of a multi-dial pressure gauge, said case having the side wall 2 which, as here illustrated, is substatially cylindrical and which is open at front and rear. The exterior surface of the case, as

a platform portion 9 through which is an aperture here illustrated, is externally screw threaded for engagement by internal screw threads provided in the cover rings 3 and 4 respectively. The front cover ring 3 has a central aperture in which is fitted the transparent panel 5, while the rear cover ring 4 is furnished with the transparent panel 6. A dial 1 is arranged within the case behind the panel 5, and a second dial 8 is arranged within the case behind the panel 6. While the gauge caps or covers here illustrated are of the usual type, includingan outer ring which supports an independent transparent panel, it is to be understood that caps or covers of othertype may be employed if desired.

The lower part of the case is provided with a I0 (Fig. 2) for the accommodation of the stem portion H of the movement support. The stem terminates in the externally screw-threaded inipple l2 to which the pressure supply conduit may be attached. The stem ,II is integrally joined to an attachingflange l3 which rests upon the uppers'urface of the platform 9, to which it is secured by means of screws M. A boss l5 projects upwardly from the flange I3 and has an internal chamber I6 (Fig. 3) which communicates with-the inner end of a passage I 1 which leads dcwn through the stem II and nipple I2. -To the upper part of the boss I5 is secured the lower end of a movement supporting standard l8. Thisstandard, as illustrated in Fig. 2, is preferably narrow in the front-to-rear direction, but has a wide upper portion designed to form a plate-like support to whichthe gauge movements are secured. The standard 3 is interposed between the front and rear gauge movements. The gauge movements are substantially identical in construction, but are placed back to back, so that the index or pointer of each gauge movement turns in a clockwise direction when viewed through the corresponding transparent panel 5 or 6 respectively.

The index staffs 33 and 33 of the respective gauge movements are in axial alignment, but by reason of the back-to-back location of the movements, and the arrangement of the link and lever connections these two staffs turn in opposite directions, but to the same amount. The pointers or indexers 35 and 25 are fixed to the outer ends of the respective index staffs and in front of their respective dials, and these dials are provided with stop pins 36 and 36 respectively to prevent reverse movement of the indexes beyond the zero points of the respective scales. The dials are provided with graduated scales, the

graduations being arranged for direct reading;

that is to say, movement of the index or pointer begins at the actual zero of pressure, the movement of the pointer or index over the scale being in direct ratio to the increase in pressure in the chamber l6.

The upper central part of the case of the inwhich houses a gauge movement including an index staff, is provided with a side wall having an aperture therein, and an open-ended lamp housstrument is provided with an opening 31, Fig. l,

over which is arranged a lamp housing 38. As here illustrated, this housing is cylindrical elongate contour and is integrally jointed to the wall 2 of the casing-the lamp of substantially ing which bridges said aperture and which is integrally united to the side wall of the case, said housing being substantially cylindrical with its axis perpendicular to the vertical plane of the index staff, the opposite ends of the housing being disposed symmetrically with respect to the vertical mid-plane of the case, the housing having an aperture in its side wall which registers with'the aperture in the side wall of the case, the

chamber or space within the housing 38 opening into the space between the two dials! and 8;

The opposite ends of this housing 38 are open but normally closed by means of removableand interchangeable end caps. The end cap 39 has a flange 40 which fits against the end of the 1 housing, and the cap is removablyheld in place by means of wing-bolts 4|. The'cap 39 is properly shaped and arranged'to provide a chamber for'the reception of the base of a lamp socket 42, designed to receive a lamp 43-disposed directly above the center of the gauge case. Theend member 39 is preferably provided with a downwardextension 44 having an internally screwthreaded opening 45 designed to receive the a threaded end of a suitable conduit through which electrical conducting wires may enter and be connected to the lamp socket.

The opposite end' of'the housing 38 is closed by a cap 46 which is normally held to the housing by'screws 41.

The dials l andB, are'of light transmitting material, preferably, translucent, for instance frosted glass, so'that light from the space between the dials mayv pass outwardly through the dials and thus provide a substantially, uniform illumination for the scales carried by the exposed surfaces of thedials. As the lamp is housed within the opaque housing 38, its light cannot escape directly forward so as to dazzle the eyes of the observer andthu the illuminated dials are very easy to read Moreover, the arrangement provides for the use of a lamp of substantial size, so thatthe chamber between th dials may be flooded with light, thus insuring sufficient intensity of illumination at all points on the'dial.

While one desirable embodiment of the invention has herein been illustrated and described, it

is to beunderstood thatthe invention is not necessarily limited to the precise'arrangements herein described, but is to be regarded as broadly inclusive-of any and all, equivalent constructions such as fall within the scope of the appended claims.

I claim:

1 An instrument opposite ends of the housing being alike and shaped for the reception of interchangeable closure caps, and interchangeable, removable caps normallyrclosingthe opposite ends of the hous- 5 ing, one of said caps being provided with a lamp socket-"so arranged as to support a lamp within the housing and above said aperture in the side wall of the housing, said latter cap also having an external hollow extension for the accommodation of anelectrical conductor leading to the socket. a

2. An instrument of the class described comprising a case having aside wall which is open at frontand rear, transparent panels normally closingthe 'front'and rear of the case respectively, a pair'of axially spaced graduated dials within thercase, eachdisposed behind and parallel tonne of saidtransparent panels, an index cooperable with each respective dial, index actuating; mechanism, including coaxial index staffs,

disposed within the space between the dials, the

.case supporting an external open-ended lamp housing, said housing being elongate and having its opposite ends disposed at substantially equal distances at opposite sides respectively 'of'the vertical mid-plane of the case and having its longitudinal axis substantially in that vertical plane which is midway between the planes'of the dial, the side wall of'the case and housing intersecting andlintegrally merging and having registering openings; the opposite ends of the housing ,being'alike. and so constructed and ar of the kind wherein a case, 7

FRANK H. HOPKINS. 

